feat: add BPO1 and BPO2 hardfork support#9
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Gabriel-Trintinalia merged 3 commits intoConsensys:mainfrom Mar 16, 2026
Merged
feat: add BPO1 and BPO2 hardfork support#9Gabriel-Trintinalia merged 3 commits intoConsensys:mainfrom
Gabriel-Trintinalia merged 3 commits intoConsensys:mainfrom
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Add BPO1 (Blob Parameter Only fork 1, EIP-7892) and BPO2 SpecId variants between Osaka and Amsterdam, with corresponding blob fraction and max blob count constants. - Add `bpo1` and `bpo2` to `SpecId` enum (between osaka and amsterdam) - Add `HardforkName.BPO1`/`BPO2` string constants - Add `specIdFromString`/`specIdToString` mappings for BPO1/BPO2 - Add `BLOB_BASE_FEE_UPDATE_FRACTION_BPO1` (8346193) and `_BPO2` (11684671) - Add `MAX_BLOB_NUMBER_PER_BLOCK_BPO1` (15) and `_BPO2` (21) - Add `BLOB_BASE_FEE_UPDATE_FRACTION_CANCUN` alias for clarity - Map bpo1/bpo2 to Osaka precompile set in `PrecompileSpecId` Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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The new bpo1/bpo2 SpecId variants were added but blobBaseFeeUpdateFraction only checked for Prague, returning 3,338,477 for all post-Prague forks instead of the correct values. Cascade the spec check to return the correct fraction per fork: - BPO2+: 11,684,671 (BLOB_BASE_FEE_UPDATE_FRACTION_BPO2) - BPO1+: 8,346,193 (BLOB_BASE_FEE_UPDATE_FRACTION_BPO1) - Osaka+: 5,007,716 (BLOB_BASE_FEE_UPDATE_FRACTION_OSAKA, EIP-7691) - Cancun+: 3,338,477 (BLOB_BASE_FEE_UPDATE_FRACTION_CANCUN) Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
garyschulte
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Mar 16, 2026
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Just the one error on Blob base fee update fraction - presuming I am interpreting https://eips.ethereum.org/EIPS/eip-7892 correctly
BLOB_BASE_FEE_UPDATE_FRACTION_OSAKA (5007716) is renamed to BLOB_BASE_FEE_UPDATE_FRACTION_PRAGUE since EIP-7691 activates at Prague, not Osaka. The redundant Prague alias for the Cancun fraction (3338477) is removed. blobBaseFeeUpdateFraction now branches on .prague instead of .osaka. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
bpo1andbpo2to theSpecIdenum (positioned betweenosakaandamsterdam)HardforkName.BPO1/BPO2string constants and wire them intospecIdFromString/specIdToStringBLOB_BASE_FEE_UPDATE_FRACTION_BPO1= 8346193 (EIP-7892)BLOB_BASE_FEE_UPDATE_FRACTION_BPO2= 11684671MAX_BLOB_NUMBER_PER_BLOCK_BPO1= 15MAX_BLOB_NUMBER_PER_BLOCK_BPO2= 21BLOB_BASE_FEE_UPDATE_FRACTION_CANCUNalias for claritybpo1/bpo2to the Osaka precompile set inPrecompileSpecIdTest plan
zig build test)specIdFromString("BPO1")/specIdFromString("BPO2")resolve correctlyspecIdToString(.bpo1)/specIdToString(.bpo2)return"BPO1"/"BPO2"isEnabledInordering: osaka < bpo1 < bpo2 < amsterdam🤖 Generated with Claude Code
Note
Medium Risk
Introduces new
SpecIdvariants and updates default blob-parameter selection based on hardfork ordering, which can affect fee calculation behavior across forks if the spec mapping is incorrect. Changes are localized but touch consensus-sensitive constants and fork gating logic.Overview
Adds support for the new blob-parameter-only hardforks
bpo1andbpo2by extendingSpecIdplus string parsing/formatting (specIdFromString/specIdToString).Updates blob-related constants (new BPO1/BPO2 base fee update fractions and max-blobs-per-block values, plus a clarified Cancun constant) and changes
CfgEnv.blobBaseFeeUpdateFraction()to derive the default fraction viabpo2/bpo1/prague/cancunprecedence when the config override is unset.Treats
bpo1andbpo2as using the Osaka precompile set by mapping them toPrecompileSpecId.OsakainPrecompileSpecId.fromSpec().Written by Cursor Bugbot for commit 5b439ff. This will update automatically on new commits. Configure here.